From afar, the acacia trees look like they have been decorated with grass pom-poms. The birds have been busy, building shelters of straw and grass. Up close the real shape of the “pom-poms” becomes clear: grass tubes in the form of an upside down “U”, with an opening at each end. These structures are the work of white-browed sparrow weavers (Plocepasser mahali). White-browed sparrow weavers are cooperative breeders. Within a multi-generational family group, only one dominant pair will reproduce; all other birds, which are mostly kin (related), will help with the rearing of chicks. These birds do everything together: forage,…